In mining and construction, wear parts (e.g., teeth, shrouds, and lips) are commonly provided along the edges of excavating equipment to protect the underlying equipment from undue wear and, in some cases, also perform other functions such as breaking up the ground ahead of the digging edge. For example, buckets for dragline machines, cable shovels, face shovels, hydraulic excavators, and the like are typically provided with multiple wear components such as excavating teeth and shrouds that are attached to a lip of a bucket. A tooth typically includes an adapter secured to the lip of a bucket and a wear member attached to the adapter to initiate contact with the ground and break up the ground ahead of the digging edge of the bucket.
During use, the wear parts typically encounter heavy loading and highly abrasive conditions that at times cause the wear parts to become disengaged and lost from the excavating machine. For example, as a bucket engages the ground a wear member, also known as a point, occasionally will be lost from the adapter. The operators of the excavating machines are not always able to see when a wear part has been lost. It is well known that a lost wear part may cause damage to downstream excavating equipment. For example, a lost wear member may cause damage that leads to additional downtime for conveyors, screens, pumps, and crushers. If a wear part becomes caught in a crusher, the wear part may be ejected and cause a hazard to workers or it may be jammed and require an operator to dislodge the part, which at times may be a difficult, time-consuming and/or hazardous process. Additionally, continuing to operate the excavating equipment with missing wear parts can lead to a decrease in production and excessive wear on other components on the excavating equipment.
The abrasive environment causes the wear parts to eventually become worn. If the wear parts are not replaced at the appropriate time, an excessively worn wear part can be lost, production may decrease, and other components of the excavating equipment may experience unnecessary wear.
Systems with varying degrees of success have been used to monitor when a wear member has been worn or damaged and needs replacement. For example, the Tooth-Wear Monitoring system and Missing Tooth Detection system sold by Motion Metrics uses an optical camera mounted on a shovel boom of excavating equipment. In addition, U.S. Pat. No. 8,411,930 relates to a system and method for detecting damaged or missing wear members. The system has a vibration resistant video camera that is preferably mounted on a shovel boom. Because the above systems are located on the shovel boom, the systems only have a clear view of the wear members during a portion of the digging and dumping operation. As a result, there is potential for the systems to not immediately register that a wear member has been lost or needs replacement. In addition should the systems incorrectly register that a wear member has been lost, the systems may have to wait until the next digging and dumping cycle to confirm that the wear member is truly lost and that an object was not obstructing the systems view and registering a false alarm.
Other systems with varying degrees of success have been used to monitor if a wear member is secured to the base on an excavating machine. For example, mechanical systems have been fixed between the wear member and the base for detecting the absence and presence of the wear member. In U.S. Pat. No. 6,870,485, the system contains a spring loaded switch between the wear parts. When the wear parts are separated an electrical switch activates a radio transmitter alerting the operator that a wear part has been lost. In U.S. Pat. No. 5,743,031, the system comprises an indicator attached to the tooth and an actuator secured to the nose. In one example, the actuator actuates, a smoke canister to provide a visual signal that the tooth has fallen off or is about to fall off. These systems do not determine when a wear member has reached the end of life and needs to be replaced and these mechanical systems can be costly and cumbersome to install when a wear member is worn and needs replacement.